Keys to success

Defending champion Madison Keys was down a double break in the second set before rallying to beat fellow American Ashlyn Krueger 6-1, 7-5.

"Once I kind of got back momentum I just tried to sink my teeth into the set," Keys said of the second set.

Melbourne is where Keys made her Grand Slam breakthrough 12 months ago, and throughout her entire trip back so far, people have been asking her how confident she is about defending a major for the first time.

"The emotions are maybe just, like, a little bit more heightened," she said. "I think in those tough kind of moments like today, getting down in that second set, just kind of reminding yourself that you have been here before, you figured it out."

Besides, she told the crowd in her on-court interview, winning the Daphne Akhurst Memorial Cup last year will always remain a permanent highlight.

"That was such an amazing experience and nobody can take that away from me," she said. "Whether or not I do repeat it, I still get to keep Daphne at home!"

Six-time Grand Slam winner Iga Swiatek turned on the style to motor past Marie Bouzkova and into the third round Thursday as she limbers up for a crack at a first Melbourne title.

The Polish second seed was in cruise control against the Czech player as the sun went down at John Cain Arena, sprinting to the finish 6-2, 6-3 in front of a vocal group of fans.

In men's play, US qualifier Spizzirri advanced at the expense of China's Wu, 6-2, 6-4, 6-7.

Lorenzo Musetti, the fifth seed, beat fellow Italian Lorenzo Sonego 6-3, 6-3, 6-4.

American eighth seed Ben Shelton was a comfortable 6-3, 6-2, 6-2 victor over Australia's Dane Sweeny.